Factors mediating pre-existing autism diagnosis and later suicidal thoughts and behaviors: A follow-up cohort study

Individuals diagnosed with autism spectrum disorder (ASD) are more likely to have suicidal thoughts and behaviors. However, little research delineates the temporal and mechanistic associations between potential risk factors and suicidality in autistic individuals. We assessed 129 autistic and 121 age-matched and sex-assigned-at-birth-matched typically developing (TD) children and youth at baseline and follow-up. We evaluated internalizing/externalizing problems, bullying experiences, and three executive function tasks at a mean baseline age of 13.4 years (standard deviation: 4.2 years). After an average of 5.8 years (standard deviation: 1.7 years), we evaluated their suicidal thoughts and behaviors. The experiences of being bullied partially mediated the temporal relationship between pre-existing ASD and later-reported suicidal thoughts. Several cognitive flexibility and sustained attention indices mediated the temporal relationship between pre-existing ASD and later-reported suicidal thoughts. A multiple mediation model confirmed that bullying victimization and cognitive flexibility jointly mediated the temporal relationship between ASD and suicidal thoughts. Better cognitive flexibility and experiences of bullying victimization in autistic children/youth were both associated with higher risks of later-reported suicidal thoughts in adolescence/adulthood. School bullying-prevention programs and tailored clinical support for autistic youth with better cognitive flexibility are warranted for personalized suicide prevention for the autistic population. Lay Abstract Autistic people are more likely to experience suicidal thoughts and behaviors. The underlying relationships between potential risk factors and suicidal thoughts and behaviors in autistic individuals remain unclear. To understand this, we investigated whether specific factors in childhood/youth explain the effects of pre-existing autism spectrum disorder (ASD) diagnoses on later suicidal thoughts and behaviors in adolescence/adulthood. We assessed internalizing and externalizing problems, bullying experiences, and executive functions (including cognitive flexibility, sustained attention, and spatial working memory) at an average baseline age of 13.4 years and suicidal thoughts and behaviors at an average follow-up age of 19.2 years among 129 autistic and 121 typically developing (TD) individuals. During the follow-up period in adolescence/adulthood, autistic individuals were more likely to report suicidal thoughts than TD individuals. Being bullied partially accounted for the relationship between a pre-existing ASD diagnosis and later-reported higher suicidal thoughts. Contrary to our hypothesis, higher (instead of lower) cognitive flexibility in some autistic young people appeared to partially explain their higher rates of suicidal thoughts compared with typically developing young people. The findings imply that school bullying prevention and tailored intervention programs for autistic people, especially those with higher cognitive flexibility, are warranted to reduce their risks of experiencing suicidal thoughts.